Sumer is Icumen in (The Hilliard Ensemble)

https://www.youtube.com/watch?v=sMCA9nYnLWo

Listen to this version for the purest pronunciation of the Wessex dialect.

The round is sometimes known as the Reading rota because the manuscript comes from Reading Abbey though it may not have been written there. It is the oldest piece of six-part polyphonic music (Albright, 1994). Its composer is anonymous, possibly W. de Wycombe, and it is estimated to date from around 1260. The manuscript is now at the British Library. The language is Middle English, more exactly Wessex dialect.